WO2005106438A1 (TITECH VISIONSORT AS) relates to an apparatus and method for inspecting a stream of matter by light scattering inside the matter. FIG. 1 in WO2005106438A1 discloses a system comprising a probe including an emitting device which emits a detection medium in the form of beams of electromagnetic radiation of a substantially constant intensity which are incident to some matter, which has a variety of lamina variations within its body. Once the incident beams reach the surface of the matter, some of the radiation penetrates the surface of the matter and is scattered within the matter and varied by the lamina variations within the matter. The scattered varied medium then passes out of the matter through the top surface as rays, a portion of which rays are focused using a lens, onto a detection device for generating detection data in dependence upon the varied radiation. However, the system in FIG. 1 in WO2005106438A1 is a point measuring device, and it needs a fixed distance between the matter and the lens.
Further, FIGS. 2-3 in WO2005106438A1 discloses a system for automatically inspecting a stream of matter for varying composition, comprising a row of lamps serving to emit a detection medium via a focusing cylindrical mirror to an irradiated zone of the stream at which the medium penetrates a surface of the matter, the irradiated zone extending continuously across substantially the width of the stream, a rotary polygonal mirror for receiving the varied medium emanating from the matter via a cylindrical lens at a detection zone, and a detecting device serving to generate detection data in dependence upon the varied medium. The system further comprises a blackened metallic screen for suppression of stray radiation. However, when the height of the matter varies beyond the lamps' focus on the matter, reflection detection will occur rather than transflection, which will negatively affect the inspection. Further, the screen physically limits the height of matter to be inspected.